Loose Lips sink ships

Loose Lips sink ships : Phrases

Meaning:

You must keep this secret or there will be a price paid.

Example:

Do not discuss any of our plans outside this boardroom, remember loose lips sink ships.

Origin:

Popularized by U.S. military propaganda during World War II. The phrase was meant as a reminder that classified information was never to be discussed with anyone without proper clearance and a need to know.

Specifically the phrase means that disclosing a military secret to the enemy could result in large loses, such as the sinking of an entire ship.